Changeable Hawk-Eagle
Nisaetus cirrhatus
凤头鹰雕
Introduction
Large bird of prey in family Accipitridae, subfamily Aquilinae. Formerly placed in genus Spizaetus but molecular phylogenetic studies resulted in Old World members being moved to genus Nisaetus. Range extends across Indian subcontinent and Southeast Asia from Himalayan foothills through Burma, Thailand, Malaysia to Indonesia, Philippines and Sri Lanka. Inhabits various wooded and semi-open habitats including savanna woodland, agricultural land, wetlands, plantations, forest villages, suburbs and undisturbed evergreen forest from sea level to 2,200m. Among the most widely distributed, adaptable and abundant Nisaetus species. Shows extreme plumage variation from pale to dark morphs depending on subspecies, age and molt, giving rise to common name. Agile forest-dwelling predator with typical hawk-eagle adaptations: long tail, short broad wings, powerful legs enabling maneuverability in dense cover.
Description
Largish but slender eagle near middle size among Nisaetus species. Total length 51-77 cm, wingspan 100-160 cm. Females average 7% larger than males but individual size difference can range 18-22%. Weights 1.2-1.9 kg in Philippines averaging 1.36 kg males and 1.6 kg females. Adults dark brown above with boldly streaked below, variably sized often floppy crest or no crest, short wings, long thinly-barred tail and long feathered legs. Perches bolt upright with wings reaching one-third to halfway down tail. Plumage polymorphism includes pale morph (white to buff underparts with black streaking), intermediate morph (grey-brown underparts with obscure streaking), and dark morph (chocolate-brown to almost pure black). Crest length varies from absent to 10-14 cm in nominate subspecies. Juvenile plumage differs substantially: dark brown above with conspicuous white edges, buff or whitish head, variable streaking below. Eyes yellow to orange in adults, grey-brown to pale greenish in juveniles. Cere grey to pale greenish yellow, feet yellow.
Identification
In most of range, most common and widespread Nisaetus species. Typically appears nearly crestless while other Nisaetus have proportionately broader wings with more bulging secondaries, shorter tails and more barred underparts as adults. Mountain hawk-eagle, Flores hawk-eagle and Legge's hawk-eagle are all larger and bulkier; Wallace's and Blyth's hawk-eagles are distinctly smaller. Pale morph shows bold black streaking on white-buff underparts; dark morph is chocolate-brown to black with contrasting pale grey tail. Flight profile shows prominent head, short rounded broad wings, long squarish tail, fast agile flight with powerful shallow beats and glides on flat wings. Crested honey buzzard mimics Nisaetus appearance but has smaller head, longer narrower wings and more robotic flight style. Juvenile crested serpent eagles appear chunkier with bigger head and shorter tail.
Distribution & Habitat
Extensive range covers Indian subcontinent and Southeast Asia. In South Asia: Garhwal Himalaya through Assam, southern Nepal and Bhutan, Sri Lanka, peninsular India north to Rajasthan, Uttar Pradesh, Bihar, Odisha and Andaman Islands. In Southeast Asia: Myanmar, Thailand, Peninsular Malaysia, western Laos, southern Vietnam, Cambodia. In Indonesia: Sumatra, Simeulue, Mentawai, Riau islands, Bangka, Belitung, Java, Borneo. In Philippines: Palawan, Calamian Islands, Lubang, Mindoro, Mindanao and Bohol. Inhabits savanna woodland, agricultural land, wetlands, tea plantations, forest villages, suburbs, evergreen forest, tropical dry broadleaf forest and secondary forest. Mainly below 1,500m elevation but recorded to 2,200m. Partial populations may make local movements but generally considered resident.
Behavior & Ecology
Diet is opportunistic and indiscriminate, primarily birds but also mammals, reptiles and other vertebrates. Prey ranges from small lizards and mynas to large items including junglefowl, peafowl, hares up to 2.7 kg, giant squirrels, monkeys up to 6 kg, monitor lizards and deer. Hunting strategies include ambush from concealed perches, perch-hunting with short low-level flights, and dropping on prey from nests. Breeds solitarily in pairs, often for life. Aerial displays involve shooting up vertically, nose-diving, and lightning-speed loop-the-loop turns. Breeding season varies by region: November-May in southern India peaking January-March, January-April in Himalayas, year-round in Greater Sunda Islands with peaks February-March and July-August. Nest is large stick structure 95-105 cm across, built 6-50m high in large tree crown. Single coarse white speckled egg incubated by female for approximately 40 days. Nestling period 60-68 days, independence around 81 days. Vocalizations are high-pitched screams: yeep-yip-yip-yip, kwip-kwip-kwip-kwee-ah, and klee-leeuw. Mostly silent outside breeding season.
Conservation
IUCN Red List status and global population figures not explicitly stated. Considered exceptionally adaptable, persisting while other Nisaetus species have declined due to deforestation. Four Nisaetus species classified as Endangered but this species shows stable or increasing populations across Indian subcontinent, Malaysia, Java and Philippines. Ranges over 13 million square kilometers with density potentially well into five figures. Remains in all seven habitat types in Java while Javan hawk-eagle confined to four. Main threats include complete deforestation eliminating tall trees, and local persecution for hunting chickens during breeding. Island taxa (N. c. andamanensis, N. c. vanheurni, and N. floris) at higher extinction risk due to founder effects and restricted genetic diversity. Requires tall trees, appropriate habitat composition and ample prey populations.
Culture
No specific cultural significance or folklore mentioned in source material.
Source: Wikipedia · CC BY-SA 3.0
Taxonomy
- Order
- Accipitriformes
- Family
- Accipitridae
- Genus
- Nisaetus
- eBird Code
- y00839
Vocalizations
Subspecies (5)
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Nisaetus cirrhatus andamanensis
Andaman Islands
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Nisaetus cirrhatus ceylanensis
Sri Lanka
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Nisaetus cirrhatus cirrhatus
peninsular India
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Nisaetus cirrhatus limnaeetus
northern India to Indochina, Malaya, Greater Sundas, and Philippines
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Nisaetus cirrhatus vanheurni
Simeulue Island (off western Sumatra)
Data Sources
Species description from Wikipedia, licensed under CC BY-SA 3.0.
Bird images and sounds sourced from GBIF, contributed by citizen scientists worldwide under Creative Commons licenses.
Taxonomy data from AviList 2025.